Insole assembly for increasing weight of footwear and heavy footwear having weight-increasing midsole/outsole

ABSTRACT

An insole assembly for increasing the weight of a footwear and a heavy footwear having an outsole and/or a midsole made of a high specific gravity compressed resin to enhance exercise effect. The insole assembly ( 100, 200 ) includes a lower insole ( 110, 210 ) made of a compressed resin having a high specific gravity; an upper insole ( 120, 220 ) laid on the lower insole ( 110, 210 ) and a shock absorbing member ( 130, 230 ) attached to a heel of the lower insole ( 110, 210 ). The insole assembly is made of a compressed resin to increase the weight of a footwear to which the insole assembly is applied.

TECHNICAL FIELD

The present invention elates to a heavy footwear of increased weight.More particularly, the present invention relates to an insole assemblymade of compressed resin for potentially increasing the weight of afootwear to which the insole assembly is applied. Further, the presentinvention relates to a heavy footwear including an outsole and/or amidsole made of a compressed resin having a high specific gravity toenhance exercise effect.

BACKGROUND ART

Various techniques have been proposed, which can increase the weight ofa footwear if necessary to enhance the exercise effect of a wearer whilekeeping the weight decreased at normal times.

An example of such techniques is disclosed in Korean Registered UtilityModel Serial No.285242, entitled “Sports Shoes for Exercise”. Accordingto this document, heavy metal members are detachably inserted into anoutsole or a bottomsole as the outer bottom portion of a footwear inorder to enhance the exercise effect of a wearer.

Another example is disclosed in Korean Registered Utility Model SerialNo.298008, entitled “Weight Adjustable Footwear Liner”, proposed by theinventor. This document proposes insertion of metal members into aninsole or liner; which is put in a footwear body, to increase the weightof the footwear thereby enhancing the exercise effect of a wearer.

According to the conventional techniques, high specific gravity materialsuch-as metal, which is inserted into the outsole or the insole forincreasing the weight of shoes, lowers the shoes ability of absorbingthe load impact applied to a wearer thereby requiring additionalshock-absorbing means.

Because additional molds as well as fabrication and assembly processesare necessary in order to provide a detachable structure for theweight-increasing insert members, the prior arts have another drawbackthat increases fabrication time and cost.

The insert members made of metal cause inconvenience to a person in theabove footwear or shoes that he/she should take off the shoes orseparate the metal members from the shoes when passing through anairport scanner.

Also the shoes may be soiled from the rust of the metal members whenwater-washed in a washing machine.

Furthermore, if the shoes are used for a predetermined time period, therubber outsoles are abraded exposing the metal members, which in turncollide against the ground creating unpleasant noises.

Therefore, there are required novel means that can overcome theforegoing problems while adjusting the weight of shoes.

DISCLOSURE OF THE INVENTION

It is therefore an object of the invention to provide an insole assemblywhich can increase the weight of a footwear when attached the footwear.

It is another object of the invention-to provide-an insole which ismolded from heavy compressed resin to impart a desired level of bodyload-absorbing ability to a footwear without additional shock-absorbingmeans.

It is further another object of the-invention to insert aweight-increasing member into a midsole and/or an outsole to increasethe weight of a footwear.

It is yet another object of the invention to fabricate a midsole and/oran outsole from a high specific gravity compressed resin to increase theweight of a-footwear.

According to an aspect of the invention for realizing the above objects,there is provided an insole assembly used for increasing the weight of afootwear comprising: a lower insole made of a compressed resin having ahigh specific,gravity, and an upper insole laid on the lower insole.

It is preferred that the lower insole is made of a compression moldedresin.

It is also preferred that the compression molded resin has a specificgravity of at least 2.

The insole assembly may further comprise a shock-absorbing memberattached to a rear end of the upper insole.

According to another aspect of the invention for realizing the aboveobjects, there-is provided a heavy weight footwear comprising: a bodyfor housing a foot, an outsole connected to the body for supporting thefoot, at least a portion of the outsole being made of a compressed resinhaving a high specific gravity, and an insole laid on the outsole withinthe body.

It is preferred that the whole part of the outsole is made of the highspecific gravity compressed resin.

It is also preferred that the high specific gravity compressed resin isinserted into the outsole.

The heavy weight footwear may further comprise a midsole laid betweenthe outsole and the body, at least a portion of the midsole being madeof a high specific gravity compressed resin.

It is preferred that the whole part of the midsole is made of the highspecific gravity compressed resin.

It is also preferred that the high specific gravity compressed resin isinserted into the midsole.

According to further another aspect of the invention for realizing theabove objects, there is provided a heavy weight footwear comprising: abody for housing a foot; a midsole connected to the body for supportingthe foot, at least a portion of the outsole being made of a compressedresin having a high specific gravity; an outsole attached to anunderside of the midsole; and an insole laid on the midsole within thebody.

It is preferred that the whole part of the midsole is made of the highspecific gravity compressed resin.

It is also preferred that the high specific gravity compressed resin isinserted into the midsole.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of an insole assembly forincreasing the weight of a footwear according to a first, embodiment ofthe invention;

FIG. 2 is an exploded perspective view of an insole assembly forincreasing the weight of a footwear according to a second embodiment ofthe invention;

FIG. 3 is a sectional view of a lower insole shown in FIG. 2;

FIG. 4 is a plan view of FIG. 3;

FIG. 5 is a bottom view of FIG. 3;

FIG. 6 is a sectional view of an upper insole shown in FIG. 2;

FIG. 7 is a plan view of FIG. 6;

FIG. 8 is a bottom view of FIG. 6;

FIG. 9 is a side elevation view of a footwear which the insole assemblyof the invention is put in;

FIG. 10 is a side elevation view of a heavy footwear for enhancingexercise effect according to a third embodiment of the invention;

FIG. 11 is an exploded perspective view of the heavy footwear accordingto the third embodiment of the invention;

FIG. 12 is an exploded perspective view of a heavy footwear according toa fourth embodiment of the invention; and

FIG. 13 is an exploded perspective view of a heavy footwear according toa fifth embodiment of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The foregoing and other features and advantages of the invention, willbe described in detail with reference to the accompanying drawings.

FIG. 1 is an exploded perspective view of an insole assembly forincreasing the weight of a footwear for example a shoe according to afirst embodiment of the invention.

Referring to FIG. 1, the insole assembly 100 of the invention includes aweight insole or a lower insole 110 made of a compressed resin having ahigh specific gravity for increasing the weight of a shoe, ashock-absorbing member 130 attached to the heel of the lower insole 110and an upper insole 140 laid on the lower insole 110.

The weight insole or lower insole 110 embodying the essential concept ofthe invention is made by compression molding a desired resin up to aspecific gravity of about at least 2. The resin contains nitrile rubber,butadiene rubber, Barium Sulfate (BaSO₄) as high specific gravityfiller, Readoxide (Pb₃O₄), ZnO, S, stearic acid and vulcanizingaccelerator. Alternatively, the resin can be pressed, and then cut andprocessed into the form of an insole to fabricate the insole.

The high specific gravity lower insole 110 may be fabricated separatefrom the shoe so that it can be detachably attached to the shoe, orintegrally attached to the shoe via adhesive and so on if necessary.

The shock-absorbing member 130 is attached to the heel or the rear end110 b of the lower insole 110, and made of an elastic material capableof absorbing the impact load applied to a wearer during his/hermovement. Further, the rear corner of the shock-absorbing member isrounded to more effectively absorb the shock during stepping as well asensure comfortable walking.

The upper insole 140 includes a support portion 142 placed on the lowerinsole 110, an elastic portion 144 laid on the support portion 142 and afoot-sole contact portion 146 laid on the elastic portion 144 to contacta wearer's foot-sole.

The support portion 142 is made of for example Ethylene VinylacetateCopolymer (EVA) at a predetermined thickness to prevent the distortion(e.g., abduction or adduction) of a wearer's foot. Alternatively, thesupport portion 142 may be made of an elastic material at a desiredthickness to keep the wearer comfortable.

The elastic portion 144 is made of a soft material to absorb shock andso on.

The contact portion 146 is made of a soft material such as a thin clothto absorb sweat from the foot while keeping the wearer comfortable, andattached on the elastic portion 144 via adhesive.

When the insole assembly 100 is used in a shoe to increase its weight,the lower insole 110 of a desired weight is inserted into the shoe, andthen the upper insole 140 is put on the lower insole 110 in the shoe,with front and rear ends 140 a and 140 b of the upper insole 140 alignedwith front and rear ends 110 a and 110 b of the lower insole 110.

FIG. 2 is an exploded perspective view of an insole assembly forincreasing the weight of a footwear according to a second embodiment ofthe invention.

As shown in FIG. 2, the insole assembly 200 of the invention includes aweight insole or a lower insole 210 made of a compressed resin having ahigh specific gravity for increasing the weight of a footwear or a shoe,a shock-absorbing member 230 attached to the heel of the lower insole210 and an upper insole 240 laid on the lower insole 210.

The lower insole 210 is made of the same material as the lower insole110 of the first embodiment, but modified with its configuration.

Hereinafter the lower insole 210 will be described with reference inFIGS. 3 to 5, wherein FIG. 3 is a sectional view of a lower insole shownin FIG. 2, FIG. 4 is a plan view of FIG. 3, and FIG. 5 is a bottom viewof FIG. 3.

As shown in FIGS. 3 to 5, the lower insole 210 is provided in a topsurface 212 with a plurality of front concave portions 214, a rearconcave portion 218 and a plurality of longitudinal grooves 216 forconnecting the concave portions 214 and 218.

The rear concave portion 218 is engraved or recessed from the topsurface 212 to absorb any landing impact. Also, the rear concave portion218 is connected with the front concave portions 214 via the grooves 216so that the pressure applied to the rear concave portion 218 duringstepping forces air to circulate from the rear concave portion 218through the grooves 216 toward the front concave portions 214 in a shoewhile evaporating sweat and dispersing heat from the foot in the shoe.

There are a plurality of exposed vertical through holes 220 in the frontconcave portions 218. The through holes 220 are connected to a pluralityof lateral grooves 226 formed in an underside 222 of the lower insole210. Longitudinal grooves 224 are connected with bottom concave portions228, which are formed in a central portion of the underside 222, andfunction as channels for flowing air from the concave portions 228toward the vertical through holes 220.

In a region of the shoe, to which load is mainly applied from a frontregion of the foot, a circular concave portion 226 a is provided to forman air channel to absorb landing pressure and impact.

The shock-absorbing member 230 is attached to the heel of the lowerinsole 210, and made of an elastic member to absorb impact load appliedto a wearer during his/her movement. Further, the rear corner of theshock-absorbing member is rounded to more effectively absorb the shockduring stepping as well as ensure comfortable walking.

The lower insole 210 is provided with a convex portion 232 in a centralportion of the top surface 212. The convex portion 232 supports themetatarsus while functioning as a cushion together with a lower concaveportion 254 of the upper insole 240, which will be described later.

Hereinafter the upper insole 240 will be described with reference toFIGS. 6 and 8, wherein FIG. 6 is a sectional view of an upper insoleshown in FIG. 2, FIG. 7 is a plan view of FIG. 6, and FIG. 8 is a bottomview of FIG. 6.

The upper insole 240 integrally has a support portion 242 attached onthe lower insole 210, an elastic portion 244 laid on the support portion242 and a foot-sole contact portion 246 laid on the elastic portion 144to contact a wearer's foot-sole.

The support portion 242 is made of for example EVA at a predeterminedthickness to prevent the distortion of a wearer's foot. Alternatively,the support portion 142 may be made of an elastic material at a desiredthickness to keep the wearer comfortable.

The elastic portion 244 is made of a soft material to absorb shock andso on.

The contact portion 246 is made of a soft material such as-a thin clothto absorb sweat from the foot while keeping the wearer comfortable, andattached on the elastic portion 244 via adhesive.

The upper insole 240 has an anti-slip projection 252 a extended from atop front portion adjacent to a front end 240 a. The upper insole 240also-has a plurality of vent holes 248 formed adjacent to the front end240 a and a plurality of downward projections 250 formed in a frontbottom thereof. Then, the projections 250 contact the top surface 212 ofthe lower insole 210 to form a space between the underside of the upperinsole 240 and the top surface 212 of the lower insole 210 through whichair can flow when the wearer -is walking. As a result, this circulatesthe air through the shoe to evaporate sweat and disperse heat from thefoot.

The upper insole 240 is provided with a convex portion 252 b extendedlongitudinally in a middle portion of the top surface of the upperinsole 240. The convex portion 252 b supports the metatarsus of the footto disperse the load across the bottom of the shoe. The bottom of theconvex portion 252 b forms a concave portion 254 to receive the convexportion 232 of the lower insole 210, thereby supporting the metatarsustogether with the convex portion 232.

A hollow space 256 is formed in the bottom of the upper insole 240adjacent to the rear end 240 b that is touched by the heel of thewearer. The hollow space 256 is located corresponding to the rearconcave portion 218 of the lower insole 210, and three grooves 258 areformed preferably corresponding to the upper grooves 218 of the lowerinsole 210. The hollow space 256 shrinks when stepped pushing the airforward to flow from the hollow space 256 through the grooves 258 and216 and spout out through the vent holes 248 toward the front portion ofthe foot. In this fashion, the air circulates in the shoe whileevaporating sweat and dispersing heat from the foot.

FIG. 9 is a side elevation view of a footwear or shoe which the insoleassembly 100 or 200 according to the first or second embodiment of theinvention is put in.

As shown in FIG. 9, a shoe 10 includes an upper or body 12 for housingthe foot, a midsole 14 for supporting the body 12 and an outsole 16underlying the midsole 14.

The lower insole 110 or 210 and the upper insole 140 or 240 of theinsole assembly 100 or 200 are inserted in their order into the shoe 10on the midsole 14 to support the foot.

The weight or lower insole 110 or 210 is preferably made with variousweights. For example, the lower insoles are fabricated with variousweights such as 200, 400, 600 an 900 g so that a user can select adesirable weight of lower insole to adjust his/her exercise effect.

In fabrication of the footwear, lasts are adjusted according to widefoot, narrow foot and mid-foot of different foot widths. If the lowerinsoles 110 and 210 are fabricated with various thicknesses, shoes ofvarious widths can be produced without additional fabrication ofdifferent lasts for the shoes. That is, users of different foot widthscan fit their feet to shoes of the same last by selecting the lowerinsoles 110 or 210 of suitable thicknesses according to their footwidths. Further, substantially same effect can be expected by taking theupper insole 140 or 240 out but using only the lower insole 110 or 210.

A fabrication process of a weight or lower insole of the invention is asfollows: Natural rubber is mixed with synthetic rubber of nitril rubberand butadiene rubber, and then with BaSO₄ of high specific gravityfiller. Mixture is pressed with a roll press to enhance molecular massas well as plasticity and viscosity. The pressed mixture is mixed againwith ZnO, S, stearic acid, vulcanizing accelerator, and then pressedagain to prepare sheets at a thickness of about 5 mm.

The pressing is performed under the pressure of about 6 to 8 kgf/cm² ata temperature range of 130 to 160° C. for 5 to 8 mins.

In the sheets prepared as above, an upper sheet preferably has ahardness of about 45 or less, and other sheets preferably has a hardnessof about 50 to 60, and more preferably, a hardness of about 55. Theupper sheet has a relatively lower hardness to absorb the load impactamounting to about 4 to 5 times of the wearer's weight, which is appliedto wearer's feet and joins when he/she walks.

These sheets are stacked one atop another with desirable number(typically 4 to 6), loaded into a mold, and heated to form into theshape of an insole.

Then, the insole has a specific gravity of about 2.0 or more and variousmasses of about 300 to 1200 g according to filler contents at 255 mmsize, and thus can be used as weight-increasing means of shoes. Forreference, typical shoe insoles have a specific gravity of about 0.4 to0.6.

Table 1 reports physical properties of the weight insole fabricated inthe above process. TABLE 1 Test Item Unit Result Test Manual TensileStrength kgf/cm² 16 KS M 6518 Elongation % 410 KS M 6518 TearingStrength kgf/cm 9.2 KS M 6518 Specific Gravity 2.38 KS M 6518 Hardness(A-type) Scale 55 ± 1 KS M 6518 Elasticity (Steel Ball Drop) % 17 KS M6518

FIG. 10 is a side elevation view of a heavy footwear for enhancingexercise effect according to a third embodiment of the invention. Asshown in FIG. 10, a heavy footwear or shoe 300 of the invention includesa body 320 of an upper for housing, a foot, a midsole 330 connected tothe body 320 to support the foot and a bottomsole or outsole 340.underlying the midsole 330. The midsole 330 and the outsole 340 areformed of various materials and with various thicknesses according tothe type and use of shoes. Further, an insole 350 (shown in a dottedline) is put on the midsole 330 to provide a cushion to a wearer's.foot-sole.

The third embodiment of the invention has technical features ofincreasing the weight of the shoe 300 by forming the midsole 330 and/orthe outsole 340 of the shoe 300 from a compressed resin of a highspecific gravity or inserting weight-increasing members made of the highspecific gravity compressed resin into the midsole 330 and/or theoutsole 340. The high specific gravity compressed resin preferably has aspecific gravity of about 2 or more, and contains nitrile rubber,butadiene rubber, Barium Sulfate (BaSO₄) as high specific gravityfiller, Readoxide (Pb₃O₄), ZnO, S, stearic acid and vulcanizingaccelerator.

FIG. 11 is an exploded perspective view of the heavy footwear or shoe300 according to the third embodiment of the invention. Referring toFIG. 3, the heavy shoe 300 according to the third embodiment of theinvention includes the upper or body 320 for housing a foot, the midsole330 connected to the body 320 to support the foot and the outsole 340underlying the midsole 330. The midsole 330 and the outsole 340 areformed of various materials and with various thicknesses according tothe type and use of the shoe. Further, the insole 350 put on the midsole330 for providing a cushion to a wearer's foot-sole is not shown forconvenience's sake.

The midsole 330 has a weight-increasing member 332 made of a highspecific gravity compressed resin and a shell member 334 for housing theweight-increasing member 332. The weight-increasing member 332 and theshell member 334 can be fabricated as separate pieces before assembledinto one via suitable means such as adhesive. Alternatively, the wholemidsole 330 can be formed of the high specific gravity compressed resinor rubber.

The weight-increasing member 332 is preferably formed of the compressedresin having a high specific gravity of about 2 or more, and thespecific gravity thereof is determined according to a desired weight ofthe shoe 300 and the thickness of the midsole 330. The high specificgravity compressed resin preferably has a specific gravity of about 2 ormore, and contains nitrile rubber, butadiene rubber, BaSO₄ as highspecific gravity filler, Pb₃O₄, ZnO, S, stearic acid and vulcanizingaccelerator.

The outsole 340 may be formed of a conventional rubber or syntheticresin, or a wear resistant rubber or synthetic resin in order to preventeasy wearing or tearing.

FIG. 12 is an exploded perspective view of a heavy footwear or shoe 400according to a fourth embodiment of the invention. Referring to FIG. 12,the heavy shoe 400 according to the fourth embodiment of the inventionincludes a body 420 of an upper for housing a foot and an underlyingoutsole 440 connected to the body 420 to support the foot. The outsole440 has a midsole formed integral thereto, and is formed of variousmaterials and with thicknesses according to the type and use of theshoe. Further, an insole put on the outsole 440 for providing a cushionto a wearer's foot-sole is not shown for convenience's sake.

The outsole 440 has a weight-increasing member 442 made of a highspecific gravity compressed resin and a shell member 444 for housing theweight-increasing member 442. The weight-increasing member 442 and theshell member 444 can be fabricated as separate pieces before assembledinto one via suitable means such as adhesive.

The weight-increasing member 442 is preferably formed of the compressedresin having a high specific gravity of about 2 or more, and thespecific gravity thereof is determined according to a desired weight ofthe shoe 400 and the thickness of the outsole 440. The high specificgravity compressed resin preferably contains nitrile rubber, butadienerubber, BaSO₄ as high specific gravity filler, Pb₃O₄, ZnO, S, stearicacid and vulcanizing accelerator. Further, the shell member 444 may beformed of a conventional rubber or synthetic-resin, or a wear resistantrubber or synthetic resin in order to prevent easy wearing or tearing.

Alternatively, the whole outsole can be formed of the high specificgravity resin or rubber. That is, the high specific gravity rubberprovides not only a large weight but also a high wear resistance, andthus itself can function as an excellent shell member.

FIG. 13 is an exploded perspective view of a heavy footwear or shoe 500according to a fifth embodiment of the invention. Referring to FIG. 13,the heavy shoe 500 according to the fifth embodiment of the inventionincludes a body 520 of an upper for housing a foot, an underlyingmidsole 530 connected to the body 520 to support the foot and abottomsole or outsole 540 underlying the midsole 530. The midsole 530and the outsole 540 are formed of various materials and with thicknessesaccording to the type and use of the shoe. Further, an insole put on themidsole 530 for providing a cushion to a wearer's foot-sole is not shownfor convenience's sake.

The outsole 540 has a weight-increasing member 542 made of a highspecific gravity compressed resin and a shell member 544 for housing theweight-increasing member 542. The weight-increasing member 542 and theshell member 544 may be fabricated as separate pieces before assembledinto one via suitable means such as adhesive.

The weight-increasing member 542 is preferably formed of the compressedresin having a high specific gravity of about 2 or more, and thespecific gravity thereof is determined according to a desired weight ofthe shoe 500 and the thickness of the outsole 540. The high specificgravity compressed resin preferably contains nitrile rubber, butadienerubber, BaSO₄ as high specific gravity filler, Pb₃O₄, ZnO, S, stearicacid and vulcanizing accelerator. Further, the shell member 544 may beformed of a conventional rubber or synthetic resin, or a wear resistantrubber or synthetic resin-in order to prevent easy wearing or tearing.

Alternatively, the whole outsole can be formed of the-high specificgravity resin or rubber. That is, the high specific gravity rubberprovides not only a large weight but also a high wear resistance, andthus itself can function as an excellent shell member.

As set forth above, the weight-increasing members made of the highspecific gravity resin can be inserted into the outsole and/or themidsole or the whole parts of the outsole and/or the midsole can be madefrom the high specific gravity compressed resin to increase the weightof the shoe thereby remarkably enhancing the exercise effect of thewearer.

Hereinafter a fabrication process of the midsoles and/or outsoles in usewith the heavy shoes according to the third to fifth embodiments of theinvention will be described.

Natural rubber is mixed with synthetic rubber of nitril rubber andbutadiene rubber, and then with BaSO₄ of high specific gravity filler.Mixture is pressed with a roll press to enhance molecular mass as wellas plasticity and viscosity. The pressed mixture is mixed again withZnO, S, stearic acid, vulcanizing accelerator, and then pressed again toprepare sheets at a predetermined thickness, preferably, at a thicknessof about 5 mm.

The pressing is performed under the pressure of about 6 to 8 kgf/cm at atemperature range of 130 to 160° C. for 5 to 8 mins.

The sheets are prepared at a hardness of about 45 to 60, preferably, ata hardness of about 50 to 55.

These sheets are stacked one atop-another with desirable number, loadedinto a mold, and heated to form into the shape of an insole.

The weight-increasing member fabricated as above has a specific gravityof about 2.0 or more and various masses of about 300 to 1200 g accordingto filler contents at 255 mm size, and thus can be used asweight-increasing means of shoes.

The weight-increasing members fabricated via the above process havephysical properties as reported in Table 1 above.

Industrial Applicability

As set forth above, the insole assembly for increasing the weight of afootwear such as a shoe according to the invention is made from onlysynthetic rubber and/or resin to overcome various problems induced frommetal elements that are inserted into an outsole and/or an insole of ashoe.

The insole assembly of the invention can also save cost since the moldfor the weight-increasing member made of metal is not necessary and anassembly process is simplified.

Because metal is not adopted, the insole assembly of the invention canrelieve the wearer from the inconvenience of taking off the footwear orseparating metal members when he/she passes through an airport scanner.The footwear does not generate noises during walking although theoutsole is partially worn out, and thus can prolong its lifetime. Also,the footwear is not soiled since it does not rust even thoughwater-washed for a long time.

In the meantime, natural perfume and herb or medicine powder may beadded to the synthetic resin or rubber of the insole to improve foothealth.

Further, the heavy footwear according to the invention is made from onlysynthetic rubber and/or resin to overcome various problems induced frommetal elements that are inserted into an outsole and/or an insole of ashoe.

The heavy footwear of the invention can also save cost since the moldfor the weight-increasing member made of metal is not necessary and anassembly process is simplified.

Because metal is not adopted, the heavy footwear of the invention canrelieve the wearer from the inconvenience of taking off the footwear orseparating metal members when he/she passes through an airport scanner.The footwear does not generate noises during walking although theoutsole is partially worn out, and thus can prolong its lifetime. Also,the footwear is not soiled since it does not rust even thoughwater-washed for a long time.

While the present invention has been shown and described in connectionwith the preferred embodiments, it will be apparent to those skilled inthe art that modifications and variations can be made without departingfrom the spirit and scope of the invention as defined by the appendedclaims.

1. An insole assembly (100, 200) used for increasing the weight of afootwear comprising: a lower insole (110, 210) made of a compressedresin having a high specific gravity; and an upper insole (120, 220)laid on the lower insole (110, 210).
 2. The insole assembly according toclaim 1, wherein the lower insole (110, 210) is made of a compressionmolded resin.
 3. The insole assembly according to claim 2, wherein thecompression molded resin has a specific gravity of at least
 2. 4. Theinsole assembly according to claim 1, wherein the lower insole (210)has, in a top surface (212) thereof, front concave portions (214), arear concave portion (218) and a plurality of longitudinal grooves (216)for connecting the front concave portions (214) with the rear concaveportion (218).
 5. The insole assembly according to claim 1, wherein thelower insole (210) has longitudinal and lateral-grooves (224, 226)formed in an underside (222) thereof and concave portions (228) formedin a central portion of the underside (222) and connected with thelongitudinal grooves (228).
 6. The insole assembly according to claim 1,wherein the lower insole (210) has a plurality of through holes (220)for connecting-a top surface (212) with an underside (222).
 7. Theinsole assembly according to claim 1, wherein the upper insole (240) hasan anti-slip projection (252 a) in a top front portion thereof.
 8. Theinsole assembly according to claim 1, wherein the upper insole (240) hasvent holes (248) perforated vertically in a front portion thereof andprojections (250) formed in a bottom front portion thereof.
 9. Theinsole assembly according to claim 1, wherein the upper insole (240) hasa convex portion (252) extended longitudinally in a top central portionto support a metatarsus.
 10. The insole assembly according to claim 1,wherein the upper insole 240 has a hollow concave portion (254) formedin a bottom rear portion thereof.
 11. The insole assembly according toclaim 1, wherein the upper insole (140, 240) has a support portion (142,242) made of a hard resin for preventing the foot of a wearer fromtwisting and a contact portion (144) made of a thin cloth and-laid onthe support portion (142, 242).
 12. The insole assembly according toclaim 1, further comprising a shock-absorbing member (130, 230) attachedto a rear end (110 b, 210 b) of the upper insole (110, 210).
 13. A heavyweight footwear comprising: a body. (320, 420, 520) for housing a foot;an outsole (340, 440, 540) connected to the body (320, 420, 520) forsupporting the foot, at least a portion of the outsole being made of acompressed resin having a high specific gravity; and an insole laid onthe outsole (340, 440, 540) within the body (320, 420, 520).
 14. Theheavy weight footwear according to claim 13, wherein the whole part ofthe outsole (440, 540) is made of the high specific gravity compressedresin.
 15. The heavy weight footwear according to claim 13, wherein thehigh specific gravity compressed resin is inserted into the outsole(440, 540).
 16. The heavy weight footwear according to claim 13, furthercomprising a midsole (330, 530) laid between the outsole (340, 540) andthe body (320, 520), at least a portion of the midsole (330, 530) beingmade of a high specific gravity compressed resin.
 17. The heavy weightfootwear according to claim 16, wherein the whole part of the midsole(330, 530) is made of the high specific gravity compressed resin. 18.The heavy weight footwear according to claim 16, wherein the highspecific gravity compressed resin is inserted into the midsole (330,530).
 19. A heavy weight footwear comprising: a body (320) for housing afoot; a midsole (330) connected to the body (320) for supporting thefoot, at least a portion of the outsole being made of a compressed resinhaving a high specific gravity; an outsole (340) attached to anunderside of the midsole; and an insole laid on the midsole within thebody.
 20. The heavy weight footwear according to claim 19, wherein thewhole part of the midsole is made of the high specific gravitycompressed resin.
 21. The heavy weight footwear according to claim 19,wherein the high specific gravity compressed resin is inserted into themidsole (330).